Surgical impact tool

ABSTRACT

A surgical impact tool comprises an electromagnetic impactor hermetically sealed within a sterilizable housing having one or more external mechanical coupling for transmitting an impact to an object external to the tool. The housing also contains an energy storage medium rechargeable through the hermetic seal, and electronic controls operable through the hermetic seal.

BACKGROUND

The present application relates to surgical tools and more particularlyto rechargeable, electrically powered tools and methods for deliveringimpacts during surgical procedures.

Many orthopedic surgical procedures require a surgeon to deliver one ormore impact to a surgical tool, an implantable prosthesis, a tissuefastener, or directly to a bone. For example, surgical hammers are usedto position a knee implant or a hip implant with respect to a bone, orto drive a fastener such as a retaining pin, a bone nail or a tissuetack into bone, for repairing bone fractures or to reattach damagedtendons or ligaments to the bone. In addition, surgical impacts may beapplied directly to bone to prepare a hole in the bone as part of asurgical procedure, or to create local defects such as microfractures ina bone surface to induce larger scale healing at the surgical site.

Current surgical impact tools are generally configured either as aconventional hammer having a weighted head mounted at an end of anelongated shaft, or as a weighted slug that is freely slidable along ashaft between two mechanical stops. An impact of the slug against one ofthe stops is transmitted to an end of the tool, which can include afitting for temporary coupling to an implant, a fastener, or to anothertool such as a bone fracture pick or awl. While providing more controlin some surgical procedures than may be available using a conventionalhammer, slide hammers can have disadvantages including relatively largedimensions along the direction of impact, and may require two-handedoperation or additional assistance from a surgical associate.

As arthroscopic surgery becomes increasingly common, where orthopedicprocedures are performed entirely via small portals opened through thepatient's skin, precision in the positioning and gauging of surgicalimpacts becomes ever more critical to achieve desirable surgicaloutcomes. Both conventional hammers and slide hammers require thesurgeon to perform relatively large-scale, abruptly terminatedmechanical motions that can compromise this precision.

Electrically powered hammers are known in the construction arts and caninclude linear or rotary internal actuators for generating an impact,for example, as disclosed in U.S. patent application Ser. No. 09/741,786to Camp, and U.S. Pat. No. 7,789,282 to Fukinuki et al., respectively,both of which are hereby incorporated by reference herein in theirentirety, but such construction tools provide neither the control orsterility required for use in arthroscopic procedures, and a need existsfor improved surgical impact tools.

SUMMARY OF THE INVENTION

A device for delivering a mechanical impact according to the presentinvention comprises a housing having an exterior surface and an interiorsurface, a wall forming a hermetic seal between the exterior andinterior surfaces and defining an interior volume, and one or morecoupling portion of the exterior surface configured for transmitting theimpact from the housing to an object. The housing has a distal end, aproximal end and a tool axis between the ends.

Disposed within the interior volume is an electrically powered impactorfor generating the impact at an impact-receiving portion of the interiorsurface, an electrical energy storage unit that can be recharged fromoutside the housing without violating the hermetic seal, and acontroller configured for delivering electrical energy from the storageunit to the impactor for generating the impact. The controller isconfigured to receive a control signal through the wall withoutviolating the hermetic seal.

The coupling portion of the housing can be configured to directly impactthe external object, or to impact the object through an intermediatetool that can be releasably coupled to the housing. For example, thetool can be an implant insertion or extraction tool, or a microfracturepick.

In one aspect of the invention, the device has an elongated, generallycylindrical shape between the proximal and distal ends, and the impactis directed along the axis. The device can include a coupling at eitheror both of the distal and the proximal end for transmitting the impactto the object.

In another aspect of the invention, the storage unit is configured to bewirelessly charged through the wall, for example, via a magnetic field.In a further aspect of the invention, the controller is operatedwirelessly using signals transmitted through the wall. The wall can beof any construction that can transmit charging and control signals tothe components in the interior volume. In an, embodiment, the wallcomprises a substantially continuous envelope about the interior volumeand can be fabricated from metal. In an embodiment, the wall isnonmagnetic.

Preferably, the device can be operated single-handedly by a surgeon,where the surgeon can position and activate the device to deliverimpacts without using a second hand or help from an assistant.

The device can be incorporated in a system for providing an impact at asurgical site in a patient. In addition to the device, the systemincludes one or more tool bit removably mountable to the device fordelivering the impact from the tool to the surgical site, and a controltransmitter positionable in proximity to the device for transmitting asignal to operate the device. The transmitter can be removably couplableto the device. Preferably, the device is sterilizable and in anembodiment, the control transmitter is provided in single-use sterilepackaging

Yet another aspect of the present invention is a method for deliveringan impact at a surgical site. The method comprises identifying alocation associated with the surgical site for delivering the impact;positioning a hermetically sealed, electrically powered impact tool atthe location, and wirelessly activating the tool for delivering theimpact.

A surgical hammer according to the present invention comprises a housinghaving an exterior surface and an interior surface with a wall providinga hermetic seal therebetween and defining an interior volume. Thehousing has a distal end and a proximal end. An electrically poweredimpactor is disposed within the interior volume and is configured forgenerating an impact at an impact-receiving portion of the interiorsurface. A surgical impact head couples to the housing exterior surfaceadjacent the impact-receiving portion of the interior surface whereby toreceive the impact. An electrical energy storage unit is disposed withinthe interior volume and is rechargeable from outside the housing withoutviolating the hermetic seal. A controller is disposed within theinterior volume and is configured for delivering electrical energy fromthe storage unit to the impactor for generating the impact upon receiptof a control signal. The controller is configured to receive the controlsignal through the wall without violating the hermetic seal.

Preferably, the surgical impact head is releasably coupled to thehousing exterior surface. The surgical impact head can be of varioustool types such as an implant insertion tool, an implant extraction toolor a microfracture pick.

Preferably, the housing has a longitudinally extended, generallycylindrical shape between the proximal end and the distal end. In oneaspect of the invention, a second surgical impact head is provided at anopposite end of the housing from surgical impact head.

In one aspect of the invention, the wall comprises a substantiallycontinuous metallic envelope about the interior volume. In an aspect ofthe invention, the wall can comprise an optical window or an electricalfeedthrough sealed therethrough.

Preferably, the storage unit is configured to be recharged wirelesslythrough the wall, and the controller is configured to receive thecontrol signal wirelessly through the wall. The storage unit preferablycomprises a storage capacitor.

In an aspect of the invention, the wall can be penetrated by a magneticfield or a radio frequency electromagnetic field for recharging thestorage unit or receiving the control signal. A transmitter can bereleasably coupled to the exterior surface of the housing and configuredto transmit the control signal to the controller. The transmitter can bedisposed in a sheath about a portion of the device or a handle extendingoutward from the device.

A method according to the present invention provides for delivering animpact at a desired location in surgical site in a patient. The methodcomprises the steps of: positioning at the location a surgical hammercomprising an electrically powered impactor in a hermetically sealedhousing, and a surgical impact head coupled thereto; and activating theimpactor to deliver an impact through housing to the surgical impacthead at the location.

Preferably, the surgical hammer delivers a plurality of periodic impactsat the location.

In an aspect of the invention, the steps of positioning and activatingthe impactor are performed using a single hand.

Preferably, the step of activating the impactor is performed bywirelessly transmitting a control signal to the impactor through thehousing, such as via a transmitter releasably coupled externally to thehousing.

A system according to the present invention is adapted to provide animpact to a surgical site in a patient. The system comprises ahermetically sealed, rechargeable impact tool; and a control transmitterconfigured for transmitting a control signal to operate the tool todeliver one or more impact.

Preferably, one or more surgical tool bits are removably couplable tothe impact tool.

Preferably, the control transmitter is releasably couplable to theimpact tool.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention is described with particularity in the appended claims.The above and further aspects of this invention may be better understoodby referring to the following description in conjunction with theaccompanying drawings, in which like numerals indicate like structuralelements and features in various figures. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a functional block, cross sectional illustration of a surgicalimpact tool embodiment according to the present invention;

FIGS. 2A and 2B schematically illustrate exemplary embodiments ofaxially-biased impactors for a tool according to the present invention,in a schematic cross sectional views;

FIG. 3 schematically illustrates an axially non-biased embodiment of animpactor for a tool according to the present invention, in a schematiccross sectional view.

FIG. 4A illustrates an embodiment of an impact tool according to thepresent invention configured with proximal and distal bayonet-type toolcouplings;

FIG. 4B illustrates an embodiment of an impact tool according to thepresent invention configured with proximal and distal screw-threadedtool couplings;

FIGS. 5A through 5C schematically illustrate exemplary electricalcharging means for various embodiments of impact tools according to thepresent invention; and

FIGS. 6A through 6E schematically illustrate exemplary controlconfigurations for embodiments of impact tools according to the presentinvention.

DETAILED DESCRIPTION

FIG. 1 is cross sectional schematic diagram illustrating functionalaspects of an exemplary surgical impact tool 100 according to thepresent invention. The tool 100 comprises a housing 102 having one ormore impact coupling portion 104, 106 for coupling to an external objectsuch as a tool bit or a surgical implant (not illustrated in FIG. 1).The one or more coupling portion 104, 106 can be a mechanical fittingfor releasably coupling to an external component, or a selected ormodified surface portion of the housing 102, such as a flat portion, aprotruding portion, or a depressed portion configured for sustainingmultiple mechanical impacts with a selected external object. The one ormore coupling portion 104, 106 can also comprise a tool end permanentlymounted to or extending integrally from the housing 102.

The housing comprises a wall 108 having an exterior surface 110 and aninterior surface 112, the wall 108 defining and hermetically enclosingan interior volume 114. The entire tool 100 is preferably sterilizable,the hermeticity of the wall 108 sealing all components within theinterior volume 114 from the external environment of the tool 100, bothduring sterilization and during surgical use of the tool 100. Thehousing 102 and the location of the one or more coupling portion 104,106 thereon can be of any configuration functional for deliveringimpacts to external objects. In the embodiment illustrated in FIG. 1,the housing 102 is generally cylindrical, and coupling portions 104, 106are disposed at respective distal 116 and proximal 118 ends of the tool100 along an impact axis 120. In other embodiments, the tool comprises ahandle extending generally transversely from the axis 120. In stillother embodiments, the one or more coupling portion 104, 106 istransversely displaced from the axis 120 on the housing 102.

An electrically-powered impactor 122 is disposed in the interior volume114 and configured to deliver a mechanical impact to an interiorimpact-receiving portion 124 of the housing 102, for transmitting theimpact via the wall 108 to the one or more coupling portion 104, 106 andthereby to the external object. In an embodiment, as illustrated in FIG.1, the impactor 122 is configured to deliver an impact distally alongthe axis 120 and the impact-receiving portion 124 comprises a portion ofthe wall 108. In an embodiment, the impact-receiving portion 124 is amechanically reinforced portion of the wall 108. In other embodiments,the impact-receiving portion 124 variously comprises a surface coatingsuch as a resilient coating on the wall 108 to modify the impact, one ormore mechanical members extending inwardly from respective lateralportions of the interior surface 112, or a structural member extendingtransversely through the axis 120 between lateral portions of theinterior surface 112 of the wall 108.

The tool 100 further comprises a rechargeable (chargeable) electricalenergy storage unit 126 disposed in the interior volume 114 andconfigured to store electrical energy for powering the impactor 122. Thestorage unit 126 can comprise any suitable electrical energy storagetechnology, with desirable properties including high discharge currentfor providing electrical pulses to the impactor, rapid chargingcapability, and high cycle life, that is, the ability to sustain manydischarge-recharge cycles. In various embodiments the storage unit 126comprises chargeable battery storage or capacitive storage. Either ofthese electrical energy storage technologies can be used for the storageunit 126. Present capacitor technology, using devices generally termed“ultracapacitors” desirably provides more rapid charging, higherdischarge currents and greater cycle life than battery technology in anequivalently-sized package, whereas rechargeable battery technology maydesirably provide greater total stored energy per charge than isavailable using an ultracapacitor.

In an embodiment, the tool 100 comprises a capacitor for electricalenergy storage. A nonlimiting example of a capacitor suitably scaled foran embodiment of the inventive impact tool is the Model BCAP0350ultracapacitor manufactured by Maxwell Technologies Inc., San Diego,Calif. This capacitor has a capacitance of 350 Farads at a rated voltageof 2.7 volts, and a rated life of 500,000 charge-discharge cycles. Forillustrative reference only, an exemplary conventional, manuallyoperated surgical hammer having a head mass of 0.5 kilogram may be usedprovide an impact force of approximately 1500 Newtons during a nominalfour millisecond duration impact to a surgical tool or implant. Thisimpact is roughly energetically equivalent to that generated by droppingthe 0.5 kilogram mass from a height of seven meters to the impact targetunder the normal acceleration of Earth's gravity.

In an illustrative embodiment of an impactor according to the presentinvention comprising a 0.5 kilogram impact head, and with 50 percentutility of the electrical energy storable in a 350 Farad capacitor at2.7 Volts, approximately twenty impacts substantially equivalent to theimpacts according to the reference illustration above are deliverablefrom a single charge of the capacitor. In an embodiment, the 0.5kilogram impact head comprises a magnetic material such as a magneticsteel alloy, and is approximately three centimeters in diameter and ninecentimeters long. In a further embodiment, the impact head iselectromagnetically accelerated using energy stored in the capacitor,over a longitudinal path 30 centimeters in length, to deliver theimpact. Consistent with design constraints known to persons skilled inthis art, the impact head mass, physical configuration, accelerationpath length and energy storage parameters can be selected over a widerange of requirements for various surgical environments. For example,impacts optimized for driving a hip replacement stem into a femur may bemuch larger than those for driving a small diameter suture anchor intosoft bone. In an embodiment, the impacts delivered by an impactoraccording to the present invention are adjustable down from a designmaximum.

Also disposed in the interior volume 114 are functional elementscorresponding to an electronic driver 128 configured to deliver energyfrom the storage unit 126 to the impactor 122, a charging receiver 130for receiving electrical power from an external power source (notillustrated in FIG. 1) to charge the energy storage unit 126 withoutcompromising the hermeticity of the wall 108, and communicationelectronics 132 configured to receive one or more type of communicationsignal from an external control interface (not illustrated in FIG. 1)for activating and controlling the impactor 122, also withoutcompromising the hermeticity of the wall 108. In an embodiment, thecommunication electronics 132 further comprises one or both ofbidirectional communication with, or providing electrical power to, thecontrol interface. These functional elements can comprise knowntechnologies including but not limited to power transistors for theelectronic driver 128, inductive charging for the charging receiver 130,and magnetic, radio frequency, or optical coupling of communicationsignals for the communication electronics 132.

The functional elements illustrated in association with FIG. 1 can bearranged in any physical configuration and variously combined to providea tool according to the present invention. By way of nonlimitingexamples, the impactor 122 can comprise components useful for receivingexternally applied energy to charge the energy storage unit 126, thedriver 128 can be integrated with the communication electronics 132, allthe electronic components can be integrated in a single physical unit,or electronic components can be distributed about or within the interiorvolume 114 or the impactor 122.

Impactors for tools according to the present invention can comprise anymeans for using electrical energy to generate an impact from within thetool, including rotary mechanisms such as a rotary solenoid or anelectric motor incorporating a mechanical stop to a rotor component, andlinear translation mechanisms such as electromagnetic solenoid-likestructures, or piezoelectric translators. FIGS. 2A and 2B show in crosssectional views, illustrative embodiments of one type of impactor thatcan be used with the surgical impact tool 100 described hereinabove.FIGS. 2A and 2B illustrate a sliding-head impactor 134 comprising aweighted head 136 axially and slidably disposed with respect to one ormore electromagnetic coil 138. In an embodiment, the head 136 is atleast partially comprised of a ferromagnetic material. For illustrativepurposes, electrical connections among the coils 138, as well aselectrical connections among other components of the various embodimentsof the tool 100, are not necessarily explicitly shown in the Figuresherein, but are implied, the principles of such interconnections beingunderstood by a person skilled in this art.

The head 136 is seen to be resiliently biased along the axis 120, forexample, by a spring 140. In FIGS. 2A and 2B, the spring 140 isillustrated as anchored distally to the housing 102, but in otherembodiments a spring or other biasing element can instead be anchoreddirectly or indirectly at any longitudinal position with respect to thehousing 102. In different embodiments, the head 136 is biased eitherproximally or distally along the axis 120.

In one embodiment, the spring 140 biases the head 136 proximally,illustrated as the head's axial position in FIG. 2A. In this embodiment,the spring 140 as illustrated in FIGS. 2A and 2B would be termed acompression spring. In this embodiment, upon electrically energizing oneor more of the coils 138, in combination or in sequence, the head 136 isaccelerated distally toward and impacts upon the impact-receivingportion 124 of the housing 102, at the head's axial position illustratedin FIG. 2B, whereupon the impact is transferred externally of the toolvia the housing 102 and the one or more impact coupling 104, 106. In anembodiment, the quantity of energy delivered by the head 136 for theimpact is determined electronically via a control signal. Following theimpact, the one or more coil 138 is de-energized and the impact cycle iscompleted by the resilient bias relatively slowly returning the head 136to the proximal axial position illustrated in FIG. 2A, the head 136 thenbeing available for additional impact cycles.

In an alternate embodiment, the spring 140 biases the head 136 distally,illustrated as the axial head position in FIG. 2B. In this embodiment,the spring 140 would be termed an extension spring as illustrated inFIGS. 2A and 2B. In this embodiment, upon energizing one or more of thecoils 138, in combination or in sequence, the head 136 is drawnproximally against the resilient bias toward but not necessarilyentirely to the proximal position illustrated in FIG. 2A, storing energyin the spring as a function of the head's axial displacement from thedistally biased position. At a predetermined proximal displacement ofthe head 136, or a preselected amount of energy delivered to the one ormore coil 138, the one or more coil is de-energized, releasing the head136 to accelerate under the resilient bias to impact theimpact-receiving portion 124. Following the impact, the head 136 isavailable for additional impact cycles.

In yet another embodiment, illustrated schematically in FIG. 3, theimpactor 134 includes minimal or no resilient biasing along the axis 120and the head 136 is moved proximally and accelerated distally, primarilyor entirely by energizing various ones of the one or more coil 138. Instill another embodiment, the head 136 itself comprises one or moreenergizable electromagnet coil.

In the embodiments associated with FIGS. 2A, 2B and 3, the head 136 isaccelerated distally to deliver an impact at the impact-receivingportion 124, but moved relatively slowly proximally, providing forstable handling of the tool 100. The one or more impact coupling portion104, 106 can comprise one or more of a variety of coupling means to atool bit or other external object. FIG. 4A schematically illustrates animpact tool 142 according to the present invention comprising exemplarytwist-locking or bayonet-type coupling portions 144, 146 disposedrespectively at a distal 148 and a proximal end 150 of the tool 142, forcoupling to a tool bit or other device 152, 154 having respectivecomplementary fittings 156, 158. FIG. 4B schematically illustratesanother tool 160 according to the present invention comprising exemplaryscrew-threaded coupling portions 162, 164 disposed respectively at adistal 166 and a proximal end 168 of the tool 160, for coupling to atool bit or other device 170, 172 having respective complementaryfittings 174, 176. In other embodiments, only one of a distal and aproximal end of an impact tool according to the present inventioncomprises a coupling portion. In yet other embodiments, a couplingportion is disposed intermediate between distal and proximal ends of thetool. Additionally, any coupling means suitable for retaining a tool bitor otherwise coupling to an external object can be used as a couplingmeans within the scope of the present invention, for example,frictionally or interference fit tool couplings, or attachmentsincluding retaining latches, locks, or retaining members.

Referring again to FIG. 1, the wall 108 of the housing 102, in additionto providing hermeticity, sterilizability and impact resistance foroperation of the tool 100, is configured to transmit energy from anexternal source to the interior volume 114 for charging the energystorage unit 126 via the charging receiver 128. The wall 108 is alsoconfigured to transmit communication signals to activate the impactor122 via the communication electronics 132. The wall 108 can comprise asingle, substantially continuous vessel about the interior volume, withcharging energy and communication signals wirelessly transmissiblethrough the material of the wall. Alternatively, the wall 108 cancomprise a vessel constructed primarily of a first material and havingone or more window of a second material hermetically sealed thereto, thewindow providing a port for transmitting one or both of charging energyand communication signals. Also alternatively, the wall 108 can compriseone or more hermetically sealed electrical feedthrough for transmittingone or both of charging energy and communication signals for the tool.

FIGS. 5A through 5C schematically illustrate exemplary embodiments oftools and associated charging means according to the present invention.First referring to FIG. 5A, a tool 178 comprises a substantiallycontinuous hermetic wall 180 through which energy can be wirelesslytransmitted from a charging transmitter 182 of a charging station 184 toa charging receiver 186 within the tool 178, for electrically chargingan electrical energy storage device, not illustrated in FIGS. 5A-5C. Invarious nonlimiting embodiments, the charging receiver 186 is configuredto be integral with other internal components of the tool 178, forexample, communications electronics and driver electronics for animpactor that can be one of the impactor embodiments disclosedhereinabove or another impactor. In an embodiment, the charging station184 is connected to a stationary electrical power source 188 such as anelectrical utility outlet. The wall 180 can be sealed by welding,soldering, adhesives, compression, or any other means compatible withsterilization of the tool 178, and its use in a surgical instrument.Energy received via the receiver 186 is stored within the tool 178 foruse in providing impacts when the tool 178 is used in a surgicalprocedure. In an embodiment, the wall 180 comprises a nonmagneticmetallic envelope that includes one or more of titanium, aluminum, anon-magnetic stainless steel or another nonmagnetic metal. In anotherembodiment the wall 180 comprises an electrically nonconductive materialthat can include an impact-resistant ceramic or polymeric material, oran electrically nonconductive composite material.

A variety of means can be used to charge the tool 178, by which is meantstoring electrical energy in an electrical energy storage unit withinthe tool 178. In one embodiment the transmitter 182 comprises a movingmagnetic field or a moving magnet within the charging station 184 thatinduces a ferromagnetic component within the tool 178 to move inresponse, inducing a current in an electromagnetic coil to charge thetool 178. Referring to FIGS. 2A-3 as an example, in an embodiment, thetool 100 is charged by axially reciprocating the head 136 in response toan externally applied moving magnetic field, inducing a charging currentin the one or more coil 138. Returning to FIG. 5A, in another embodimentthe charging transmitter 182 comprises a source of vibration or anacoustic signal that transmits energy through the wall 180 to thereceiver 186, which converts the vibrational or acoustic energy toelectrical energy to charge the tool 178. In yet another embodiment, thetransmitter 182 and the receiver 186 comprise an inductively-coupledcharging system. In embodiments wherein the wall 189 is electricallynonconductive, charging can be performed using a radio-frequencywireless signal. In an embodiment, placement of the tool 178 on, in, orin proximity to the charging station 184 is sensed by the station 184,automatically initiating a charging cycle.

Now turning to FIG. 5B, a tool 190 according to the present inventioncomprises a hermetic wall 192 into which is hermetically sealed one ormore electrical feedthrough 194 through which charging energy can beconductively routed from a charging transmitter 196 of a chargingstation 198 to a charging receiver 200 within the tool 190. In anembodiment, the charging station 198 is connected to the stationaryelectrical power source 188. The wall 192 and the one or morefeedthrough 194 can be joined to one another and hermetically sealedtogether by welding, soldering, adhesives, compression, or any othermeans compatible with sterilization and use in a surgical instrument.Energy received via the receiver 200 via the one or more feedthrough 194and corresponding electrical contacts 202 between the tool 190 and thecharging station 198, is used to charge the tool 190. In addition to anyof the wall materials discussed in association with the tool 178 of FIG.5A above, the wall 192 of the tool 190 in the embodiment illustrated inFIG. 5B can comprise ferromagnetic materials. Many durable hermeticelectrical feedthroughs are known in this art, includingceramic-to-metal seals well suited to harsh mechanical and chemicalenvironments. The direct electrical connections used in this embodimentfor charging the tool 190 allow high charging currents to be employed,for very rapid charging of the tool 190.

Now turning to FIG. 5C, an impact tool 204 comprises a hermetic wall 206into which is hermetically sealed a window 208 through which chargingenergy can be wirelessly transmitted from a charging transmitter 210 ofa charging station 212 to a charging receiver 214 within the tool 204.In an embodiment, the charging station 212 is connected to thestationary electrical power source 188. The wall 206 and the window 208can be joined to one another and hermetically sealed together by any ofthe sealing means disclosed above, or by any other means compatible withsterilization and use in a surgical instrument. Energy received via thereceiver is used to charge the tool 204. In one embodiment, the wall 206is optically opaque and the window 206 is optically transparent fortransmitting optical energy from the transmitter 210, comprising anoptical emitter, to the receiver 214, comprising an optical receiver. Inanother embodiment, the window 208 is configured to transmitradiofrequency energy to which the wall 206 is otherwise opaque.

The operation and control of impact tools according to the presentinvention can comprise any of a variety of interfaces. FIGS. 6A through6E illustrate several exemplary embodiments of control interfaces forimpact tools according to the present invention. Elements of theseinterfaces can be variously combined and modified, other interfaceelements can be employed, and their physical configurations can beadapted to meet specific ergonomic operating requirements, withoutdeviating from the principles of the invention. First referring to FIG.6A, illustrated with the tool 178 of FIG. 5A, a control interface 216 isshown to be configured for mechanical coupling to a proximal couplingportion 218 of the tool 178.

The control interface 216 is seen to comprise one or more controlelement 220 that in an embodiment includes one or more of an actuatorswitch and an impact adjustment control for setting the quantity ofelectrical energy imparted to the impactor to generate an impact. Thecontrol interface 216 also comprises a control transceiver 222configured for wireless communication with communication electronics 224within the tool 178. In one embodiment, the transceiver 222 comprises aradio frequency transmitter and the communication electronics comprisesa radio frequency receiver. In a further embodiment, the transceiveralso comprises a radio frequency receiver and the communicationelectronics also comprises a radio frequency transmitter. In anotherembodiment, the transceiver 222 and the communication electronics areconfigured to communicate using an acoustic signal. In yet anotherembodiment, communication between the transceiver 222 and thecommunications electronics 224 comprises positioning a magnet in thecontrol interface 216 and detection of a magnetic field of the magnetusing a magnetic sensor such as a Hall Effect Sensor in thecommunication electronics 224.

In one embodiment, the interface 216 comprises a battery for supplyingelectric power to operate the transceiver. In another embodiment, theinterface 216 receives power wirelessly from the tool 178 for poweringthe transceiver 222. In yet another embodiment, one or both of theinterface 216 and the tool 178 comprises a wireless identificationdevice to facilitate communication between the devices. In a furtherembodiment the wireless identification device is a radio-frequencyidentification device (RFID). Also illustrated in FIG. 6A is anexemplary tool bit 226 coupled to a distal coupling portion 228 of thetool 178 for delivering a distally directed impact, illustrated by anarrow in the figure.

Now referring to FIG. 6B, illustrated with the tool 190 of FIG. 5B, acontrol interface 230 is shown to comprise a sheath 232 about at least aportion of the tool 190 and mechanically coupled to a proximal couplingportion 234 of the tool 190. In an embodiment, the sheath 232 comprisesa soft or resilient material configured to absorb or dissipate a portionof an impact delivered by the tool 190. The control interface 230 isseen to include one or more control element 236 that can be an actuatorswitch or an impact adjustment control. The control interface 230 isalso seen to comprise one or more electrical contact 238 fortransmitting control signals to a control signal receiver 240 in thetool 190, via one or more hermetic electrical feedthrough 242. In anembodiment, electrical power for the control interface 230 is providedby the tool 190 via the one or more feedthrough 242. In anotherembodiment, the one or more hermetic feedthrough 242 is also used forcharging the tool 190 when the tool is disposed in contact with acharging station. Also illustrated in FIG. 6B is the exemplary tool bit226 coupled to a distal coupling portion 244 of the tool 190 fordelivering a distally directed impact, illustrated by an arrow in thefigure.

Next referring to FIG. 6C, illustrated with the windowed tool 204 ofFIG. 5C, a control interface 246 is shown to comprise a sheath 248 aboutat least a portion of the tool 204. Whereas the interface 230illustrated in FIG. 6B is shown as coupled to the proximal couplingportion 234 of the associated tool 190, the interface 246 illustrated inFIG. 6C does not couple to a proximal coupling portion 250 of the tool204, leaving the proximal coupling portion 250 accessible for proximalcoupling to a tool bit or other external object. The control interface246 is seen to include one or more control element 252 that can be anactuator switch or an impact adjustment control, and a transceiver 254configured to wirelessly communicate with communication electronics 256in the tool 204. In one embodiment, the transceiver 254 and thecommunication electronics 256 comprise an optical communication system,comprising respective optical emitters and receivers. Also illustratedin FIG. 6C is the exemplary tool bit 226 coupled to a distal couplingportion 258 of the tool 204 for delivering a distally directed impact,illustrated by an arrow in the figure.

FIG. 6D illustrates a tool 260 according to the present inventioncomprising a hermetic wall 262 having an integral control interface 264.In one embodiment, the control interface 264 comprises one or moreresilient member hermetically sealing an opening through the wall 262,wherein a mechanical force applied to flex the resilient member canengage an internal switch or other electrical device to provide acontrol signal to the tool 260. In an alternate embodiment, a toolaccording to the present invention is not hermetically sealed andcontrol and activation of the tool comprises one or more non-hermeticpenetration of a wall of the tool. Also illustrated in FIG. 6D is anexemplary proximal tool bit 266 coupled to a proximal coupling portion268 of the tool 260 for delivering a distally directed impact via ahook-shaped tool tip 270, the direction of the impact illustrated by anarrow in the figure.

FIG. 6E illustrates a mechanical variation of the control interface 216described in association with FIG. 6A, the interface 272 illustrated inFIG. 6E being configured to extend transversely from the tool 178. In anembodiment, the interface 272 comprises a pistol-type ergonomic handle274 and one or more control element 276 positioned for convenient fingeraccess when coupled to the tool 178. In various embodiments, any of theinterfaces disclosed in association with FIGS. 6A through 6E comprises asingle-use component selectable by a surgeon for use with an impact toolaccording to the present invention. In one embodiment, a selection ofthe interface is from among several available interfaces havingdifferent specifications from one another, the selection determining oneor more of a repetition rate and a magnitude of an impact delivered bythe impact tool. In an embodiment, the interface includes no internalpower source, but is powered by the tool with which it is used. Inanother embodiment, the interface includes a readout that is configuredto report the status of the charging of the tool.

Even further, in an embodiment comprising wireless communication betweenan impact tool according to the present invention and a complementarycontrol interface, the tool can be operated remotely by the controlinterface, without the control interface being physically coupled to thetool, for example, by a surgical assistant, upon request of the surgeon.Alternatively, the control interface can comprise a wirelessly coupledfootswitch for activation by the surgeon.

In an embodiment of a surgical procedure according to the presentinvention, a sterilized tool and one or more selected sterile-packagedinterface according to the present invention are provided. In oneembodiment, the tool is provided pre-charged to the surgeon. In anotherembodiment, the tool is charged using a charger located within oradjacent to the sterile surgical field, a step rendered practical forwirelessly charged tools by disposition of a sterile barrier between thetool and a potentially non-sterile charger. One of the one or moreinterface is removed from its sterile packaging and coupled to the toolto form a tool assembly. In an embodiment, a sterile surgical tool bitor an implant is also provided and coupled to the assembly.

To deliver an impact using the tool assembly, the surgeon grasps thetool and positions a working portion of the tool bit or implant at adesired location with respect to the patient. Then the surgeon thenactivates one or more control element associated with the interface todeliver one or more impact. In one embodiment, a single activation ofthe interface causes the tool to deliver a single impact. In anotherembodiment a single activation of the interface causes the tool todeliver a plurality of temporally spaced impacts. In an embodiment, thesurgeon uses a single hand to perform at least two of grasping the tool,positioning the tool, and activating the interface to deliver one ormore impact. In another embodiment, the surgeon uses a single hand tograsp the tool, position the tool, and activate the interface to deliverone or more impact. In one embodiment, the tool bit is a microfracturepick for performing a microfracture procedure on a bone. In anotherembodiment, the tool is directly coupled to an implant for impactdriving the implant into bone without using an intermediate tool bit.

Advantageously, impact tools according to the present invention enable asurgeon to deliver controlled impacts using a single hand, freeing thesurgeon's second hand to perform other surgical tasks, thereby providingopportunities to significantly enhance the surgeon's performance as wellas potentially reducing the surgeon's dependence on surgical assistantsduring complex or delicate procedures such as arthroscopic procedures.Delivery of individual impacts or groups of impacts using impact toolsaccording to the present invention can be controlled directly by asurgeon using controls incorporated into an interchangeable interface.Further, impact tools according to the present invention can bereleasably coupled to any of a variety of surgical tool bits for usewith or without applying impacts. In an embodiment, a cylindricallyconfigured impact tool according to the present invention is coupled toa surgical screwdriver bit for rotating a screw-threaded surgicalfastener, while providing the surgeon with an option to deliver impactswith the tool as needed.

Also advantageously, an impact tool according to the present inventioncan be repeatedly sterilized for multiple uses, and can be used inconjunction with simple, single use control interfaces selectablesubject to surgeon preferences regarding control functions andergonomics. In an embodiment, a single use interface according to thepresent invention is supplied to a surgeon in a sealed, sterile package.In another embodiment, an interface selectable by a surgeon ispreprogrammed to provide impacts of one or more preselected intensity ortemporal pattern.

The invention has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations insofar as they come within thescope of the appended claims or the equivalents thereof.

1-12. (canceled)
 13. A method for delivering an impact at a desiredlocation in surgical site in a patient, the method comprising:positioning at the location a surgical hammer comprising an electricallypowered impactor in a hermetically sealed housing, and a surgical impacthead coupled thereto; and activating the impactor to deliver an impactthrough housing to the surgical impact head at the location.
 14. Amethod according to claim 13 wherein the surgical hammer delivers aplurality of periodic impacts at the location.
 15. A method according toclaim 13 wherein the surgical impact head comprises a microfracture pickand the method comprises the step of creating a microfracture in a boneat the location.
 16. The method according to claim 13 wherein the stepsof positioning and activating the impactor are performed using a singlehand.
 17. The method according to claim 13 wherein activating theimpactor is performed by wirelessly transmitting a control signal to theimpactor through the housing.
 18. The method according to claim 13wherein activating the impactor comprises operating a transmitterreleasably coupled externally to the housing. 19-23. (canceled)